Hi Jeff and Welcome!
Don't hesitate on the Suburban. As far as data/information, if you can get pre-mod engine, manifold, cat converter, exh temps with an infrared thermometer, that would be great. Fuel trim and scan tool data would also be helpfull. Then do the groove, cap off the pcv and redirect it to a pre-throttle body position. Check for vacuum leaks - I believe the '98 vintage used vac operated servos for HVAC control. But DO THE MOD and please report your pre and post information. We are here to help.
Call me if you have questions - I not only play a mechanic on TV but also in real life!
My # is 1-231-203-3072
Scott Castleberg
Pellston, MI
Gadgetman Michigan